Thermodynamic And Kinetic Studies Of Protein Structure A

蛋白质结构A的热力学和动力学研究

• 批准号: 6507264
• 负责人: Allen P Minton
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6507264
• 关键词: chemical kinetics; circular dichroism; conformation; cystathionine beta synthase; enzyme activity; enzyme inhibitors; enzyme mechanism; enzyme substrate complex; glutathione; mathematical model; oxidation reduction reaction; prions; protein folding; protein sequence; protein structure; protein structure function; scrapie; spongiform encephalopathy; sulfotransferase; thermodynamics; tryptophan synthase; virus protein; virus replication

This laboratory is interested in the relationship among protein sequence, structure and the mechanisms of protein folding and enzymic reactions. (i) Secondary Structure of Insoluble Proteins. The structure of a protein in solution is readily estimated by mathematical analysis of its circular dichroism (CD)spectrum. Proteins implicated in prion diseases are insoluble and must be studied as thin films. Under these circumstances, protein concentration, which is usually necessary for quantification and analysis of CD data cannot be determined. We have shown a concentration independent method of structure determination, which involves measurement and deconvolution of the protein's "g-factor" spectrum, which is the ratio of a samples CD and absorbance spectra. (ii) Structure of Cystathionine beta Synthase (with Dr. Edith Wilson Miles and coworkers, LBG) We are investigating the conformational states of the tryptophan synthase alpha2-beta2 complex and their relevance in the enzymatic mechanism of the protein. (iii) Structure of Mammalian Sulphotransferases. (with Dr. D. Marshall and Dr. W.B. Jakoby, LBM) The enzymatic activity of a phenol sulphotransferase, from rat liver, has been shown to be regulated by reversible oxidation/reduction of a conserved specific cysteine residue by physiological concentrations of glutathione. Oxdation of cysteine residue 66 inhibits the physiological activity of the enzyme by very tight substrate inhibition. This mechanism may be important under conditions of oxidative stress to the liver. (iv) Structure of Rotavirus protein NSP2 (with Dr. Peter Schuck, ORS, OD and Dr. Z. Taraporewala, LID, NIAID) This protein is a component of the virus' replication apparatus, interacting with RNA and nucleotides. We are studying its structure and the changes induced by interaction with ligands.

本实验室主要研究蛋白质的序列、结构以及蛋白质折叠与酶反应的机制之间的关系。(i)不溶性蛋白质二级结构。通过对其圆二色性（CD）光谱的数学分析，可以很容易地估计溶液中蛋白质的结构。与朊病毒疾病有关的蛋白质是不溶的，必须作为薄膜进行研究。在这种情况下，无法确定通常用于定量和分析CD数据的蛋白质浓度。我们已经展示了一种与浓度无关的结构测定方法，该方法涉及蛋白质的“g因子”光谱的测量和反卷积，这是样品CD和吸光度光谱的比值。（ii）半胱硫氨酸- β合成酶的结构（与Edith Wilson Miles博士和同事合作，LBG）我们正在研究色氨酸合成酶α 2- β 2复合物的构象状态及其在蛋白质酶学机制中的相关性。（iii）哺乳动物硫转移酶的结构。（与Dr. D. Marshall和Dr. W.B. Jakoby博士合作，LBM）来自大鼠肝脏的苯酚硫转移酶的酶活性已被证明是由谷胱甘肽的生理浓度对保守的特定半胱氨酸残基的可逆氧化/还原所调节的。半胱氨酸残基66的氧化通过非常紧密的底物抑制抑制酶的生理活性。这种机制在肝脏氧化应激条件下可能是重要的。（iv）轮状病毒蛋白NSP2的结构（与Peter Schuck博士，ORS， OD和Z. Taraporewala博士，LID， NIAID合作）该蛋白是病毒复制装置的一个组成部分，与RNA和核苷酸相互作用。我们正在研究它的结构和与配体相互作用引起的变化。